A decade ago, my lawyers questioned Trump under oath during a deposition in a libel case he filed against me for a biography I wrote, “TrumpNation.” (Trump lost the case in 2011.) Trump had to acknowledge 30 times during that deposition that he had lied over the years about a wide range of issues: his ownership stake in a large Manhattan real estate development; the cost of a membership to one of his golf clubs; the size of the Trump Organization; his wealth; the rate for his speaking appearances; how many condos he had sold; the debt he owed, and whether he borrowed money from his family to stave off personal bankruptcy.

Trump also lied during the deposition about his business relationships with organized crime figures.

When my lawyers asked him whether he planned to sever his partnership with a developer named Felix Sater because of Sater’s mob ties, Trump said he hadn’t decided.

"Have you previously associated with people you knew were members of organized crime?" one of my lawyers asked.

"No, I haven't," Trump responded.

That wasn't true, however. Trump, despite what he said in the deposition, had knowingly associated with mob figures before.